From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id j3TKZnO15438 for ; Fri, 29 Apr 2005 16:35:49 -0400 Received: from whirlwind.atmosp.physics.utoronto.ca (whirlwind.atmosp.physics.utoronto.ca [128.100.80.80]) by mx3.redhat.com (8.12.11/8.12.11) with ESMTP id j3TKZgmM027115 for ; Fri, 29 Apr 2005 16:35:42 -0400 Message-ID: <42729A76.6050204@atmosp.physics.utoronto.ca> Date: Fri, 29 Apr 2005 16:35:02 -0400 From: Guido Vettoretti MIME-Version: 1.0 Subject: Re: [linux-lvm] large logical volumes References: <424B4459.5050207@utoronto.ca> <3b24531c0504291300587dd539@mail.gmail.com> In-Reply-To: <3b24531c0504291300587dd539@mail.gmail.com> Content-Type: multipart/alternative; boundary="------------070403010209070709000304" Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: To: Myrddin Emrys , LVM general discussion and development This is a multi-part message in MIME format. --------------070403010209070709000304 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Someone answered my reponse! Thanks Anyway. I've sorted things out. I've manage to set up a fairly large RAID fs on and intel xeon 32-bit server running RHEL4. As you suggest the solution was to go to a new fs (I chose XFS as Reiser seemed to behave strangely with LVM and the large filesystem). I just had to rebuild the kernel with xfs support. Things are running smoothly right now. In case anyone is interested there seem to be some limitations: 32-bit machines: ext3 : 2Tb (I managed to create a 4TB fs for some reason) xfs : 16 Tb reiser : 16Tb 64-bit: ext3: 2Tb (? not sure about this one) xfs and reiser: very large (> million Tb) One of the hardware support people said there was a 2Tb limit on the SCSI protocol (not sure about this), so I had to use LVM to create the large volume from a subset of RAID volumes even though the native capacity of the RAID unit was 16Tb. So the process was to divide and recollect the RAID volumes using LVM and xfs. Cheers, Guido Myrddin Emrys wrote: >Looks like you never got a response. I hardly consider myself >qualified, but have you considered increasing the block size? The >other option, have you tried a different filesystem? Different fs have >different limitations... what you're describing appears to be a >limitation of ext2fs, not LVM. Have you considered XFS or ReiserFS? > >On 3/30/05, Guido Vettoretti wrote: > > >>Hello, >> >>I'm trying to set up a large logical volume (13.1 TB) on a RHEL 4.0 >>server. I have 8 scsi devices of 1.8Tb each. >> >>When I try to do a 'mkfs' and set up a large disk I get limited to 4Tbytes. >>This command creates a smaller filesystem then >>[root@cyclone ~]# lvcreate -l 1287525 -i 3 -n lvol0 vol0 >>this one. >>[root@cyclone ~]# lvcreate -l 1000000 -i 3 -n lvol0 vol0 >> >>It seems that there is a limit on the number of block groups of 32768 >>and blocks per group of 32768. >>My block size is 4096 >>so I can only get an LV of 4096*32768*32768 = 4TB. >> >>I tried modifying the PE size on the volume group, but I'm still having >>problems. >> >>Can anyone help please? >> >>Thanks >>Guido >>--------------- >>[root@cyclone ~]# mkfs -t ext3 /dev/vol0/lvol0 >>mke2fs 1.35 (28-Feb-2004) >>max_blocks 4294967295, rsv_groups = 0, rsv_gdb = 1024 >>Filesystem label= >>OS type: Linux >>Block size=4096 (log=2) >>Fragment size=4096 (log=2) >>512016384 inodes, 1024002048 blocks >>8250429 blocks (0.81%) reserved for the super user >>First data block=0 >>Maximum filesystem blocks=1027604480 >>31251 block groups >>32768 blocks per group, 32768 fragments per group >>16384 inodes per group >>Superblock backups stored on blocks: >> 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, >>2654208, >> 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, >> 102400000, 214990848, 512000000, 550731776, 644972544 >> >>Here is the entire process I typed: >>------------------------------------------------------------------------------ >> >>[root@cyclone ~]# pvcreate /dev/sdc1 /dev/sdd1 /dev/sde1 >> Physical volume "/dev/sdc1" successfully created >> Physical volume "/dev/sdd1" successfully created >> Physical volume "/dev/sde1" successfully created >>[root@cyclone ~]# pvscan >> /dev/cdrom: open failed: No medium found >> PV /dev/sda2 VG VolGroup00 lvm2 [34.06 GB / 0 free] >> PV /dev/sdb1 VG VolGroup00 lvm2 [34.16 GB / 0 free] >> PV /dev/sdc1 lvm2 [1.64 TB] >> PV /dev/sdd1 lvm2 [1.64 TB] >> PV /dev/sde1 lvm2 [1.64 TB] >> Total: 5 [4.98 TB] / in use: 2 [68.22 GB] / in no VG: 3 [4.91 TB] >>[root@cyclone ~]# vgcreate vol0 /dev/sd[c-e]1 >> Volume group "vol0" successfully created >>[root@cyclone ~]# vgdisplay >> --- Volume group --- >> VG Name vol0 >> System ID >> Format lvm2 >> Metadata Areas 3 >> Metadata Sequence No 1 >> VG Access read/write >> VG Status resizable >> MAX LV 0 >> Cur LV 0 >> Open LV 0 >> Max PV 0 >> Cur PV 3 >> Act PV 3 >> VG Size 4.91 TB >> PE Size 4.00 MB >> Total PE 1287525 >> Alloc PE / Size 0 / 0 >> Free PE / Size 1287525 / 4.91 TB >> VG UUID fQ7cKh-FVnl-NglQ-jimv-RsZK-dU5j-zYKIcG >> >>[root@cyclone ~]# lvcreate -l 1287525 -i 3 -n lvol0 vol0 >> Using default stripesize 64KB >> Logical volume "lvol0" created >>[root@cyclone ~]# lvdisplay >> --- Logical volume --- >> LV Name /dev/vol0/lvol0 >> VG Name vol0 >> LV UUID c2MADb-BoAO-lhl3-3ukj-XfyQ-K8L0-cxcIlw >> LV Write Access read/write >> LV Status available >> # open 0 >> LV Size 4.91 TB >> Current LE 1287525 >> Segments 1 >> Allocation inherit >> Read ahead sectors 0 >> Block device 253:2 >> >>[root@cyclone ~]# mkfs -t ext3 /dev/vol0/lvol0 >>mke2fs 1.35 (28-Feb-2004) >>max_blocks 4294967295, rsv_groups = 0, rsv_gdb = 1024 >>Filesystem label= >>OS type: Linux >>Block size=4096 (log=2) >>Fragment size=4096 (log=2) >>122355712 inodes, 244683776 blocks >>12234188 blocks (5.00%) reserved for the super user >>First data block=0 >>Maximum filesystem blocks=247463936 >>7468 block groups >>32768 blocks per group, 32768 fragments per group >>16384 inodes per group >>Superblock backups stored on blocks: >> 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, >>2654208, >> 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, >> 102400000, 214990848 >> >>_______________________________________________ >>linux-lvm mailing list >>linux-lvm@redhat.com >>https://www.redhat.com/mailman/listinfo/linux-lvm >>read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ >> >> >> > >_______________________________________________ >linux-lvm mailing list >linux-lvm@redhat.com >https://www.redhat.com/mailman/listinfo/linux-lvm >read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ > > > > --------------070403010209070709000304 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Someone answered my reponse! Thanks
Anyway. I've sorted things out. I've manage to set up a fairly large RAID fs on and intel xeon 32-bit server running RHEL4.
As you suggest the solution was to go to a new fs (I chose XFS as Reiser seemed to behave strangely with LVM and the large filesystem).  I  just had to rebuild the kernel with xfs support. Things are running smoothly right now.

In case anyone is interested there seem to be some limitations:
32-bit machines:
ext3 : 2Tb (I managed to create a 4TB fs for some reason)
xfs   : 16 Tb
reiser : 16Tb
64-bit:
ext3: 2Tb (? not sure about this one)
xfs and reiser: very large (> million Tb)

One of the hardware support people said there was a 2Tb limit on the SCSI protocol (not sure about this), so I had to use LVM to create the large volume from a subset of RAID volumes even though the native capacity of the RAID unit was 16Tb. So the process was to divide and recollect the RAID volumes using LVM and xfs.

Cheers,
Guido

Myrddin Emrys wrote:
Looks like you never got a response. I hardly consider myself
qualified, but have you considered increasing the block size? The
other option, have you tried a different filesystem? Different fs have
different limitations... what you're describing appears to be a
limitation of ext2fs, not LVM. Have you considered XFS or ReiserFS?

On 3/30/05, Guido Vettoretti <g.vettoretti@utoronto.ca> wrote:
  
Hello,

I'm trying to set up a large logical volume (13.1 TB) on a RHEL 4.0
server. I have 8 scsi devices of 1.8Tb each.

When I try to do a 'mkfs' and set up a large disk I get limited to 4Tbytes.
This command creates a smaller filesystem then
[root@cyclone ~]# lvcreate -l 1287525 -i 3 -n lvol0 vol0
this one.
[root@cyclone ~]# lvcreate -l 1000000 -i 3 -n lvol0 vol0

It seems that there is a limit on the number of  block groups of 32768
and blocks per group of 32768.
My block size is 4096
so I can only get an LV of 4096*32768*32768 = 4TB.

I tried modifying the PE size on the volume group, but I'm still having
problems.

Can anyone help please?

Thanks
Guido
---------------
[root@cyclone ~]# mkfs -t ext3 /dev/vol0/lvol0
mke2fs 1.35 (28-Feb-2004)
max_blocks 4294967295, rsv_groups = 0, rsv_gdb = 1024
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
512016384 inodes, 1024002048 blocks
8250429 blocks (0.81%) reserved for the super user
First data block=0
Maximum filesystem blocks=1027604480
31251 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632,
2654208,
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
        102400000, 214990848, 512000000, 550731776, 644972544

Here is the entire process I typed:
------------------------------------------------------------------------------

[root@cyclone ~]# pvcreate /dev/sdc1 /dev/sdd1 /dev/sde1
  Physical volume "/dev/sdc1" successfully created
  Physical volume "/dev/sdd1" successfully created
  Physical volume "/dev/sde1" successfully created
[root@cyclone ~]# pvscan
  /dev/cdrom: open failed: No medium found
  PV /dev/sda2   VG VolGroup00   lvm2 [34.06 GB / 0    free]
  PV /dev/sdb1   VG VolGroup00   lvm2 [34.16 GB / 0    free]
  PV /dev/sdc1                   lvm2 [1.64 TB]
  PV /dev/sdd1                   lvm2 [1.64 TB]
  PV /dev/sde1                   lvm2 [1.64 TB]
  Total: 5 [4.98 TB] / in use: 2 [68.22 GB] / in no VG: 3 [4.91 TB]
[root@cyclone ~]# vgcreate vol0 /dev/sd[c-e]1
  Volume group "vol0" successfully created
[root@cyclone ~]# vgdisplay
  --- Volume group ---
  VG Name               vol0
  System ID
  Format                lvm2
  Metadata Areas        3
  Metadata Sequence No  1
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                3
  Act PV                3
  VG Size               4.91 TB
  PE Size               4.00 MB
  Total PE              1287525
  Alloc PE / Size       0 / 0
  Free  PE / Size       1287525 / 4.91 TB
  VG UUID               fQ7cKh-FVnl-NglQ-jimv-RsZK-dU5j-zYKIcG

[root@cyclone ~]# lvcreate -l 1287525 -i 3 -n lvol0 vol0
  Using default stripesize 64KB
  Logical volume "lvol0" created
[root@cyclone ~]# lvdisplay
  --- Logical volume ---
  LV Name                /dev/vol0/lvol0
  VG Name                vol0
  LV UUID                c2MADb-BoAO-lhl3-3ukj-XfyQ-K8L0-cxcIlw
  LV Write Access        read/write
  LV Status              available
  # open                 0
  LV Size                4.91 TB
  Current LE             1287525
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:2

[root@cyclone ~]# mkfs -t ext3 /dev/vol0/lvol0
mke2fs 1.35 (28-Feb-2004)
max_blocks 4294967295, rsv_groups = 0, rsv_gdb = 1024
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
122355712 inodes, 244683776 blocks
12234188 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=247463936
7468 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632,
2654208,
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
        102400000, 214990848

_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

    

_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
--------------070403010209070709000304--